1. Field of the Invention
The present invention is directed to screens for vibratory separators and shale shakers, supports for such screens, vibratory separators and shale shakers with such screens, and methods of using such supports, screens, separators, and shakers.
2. Description of Related Art
Vibratory separators are used in a wide variety of industries to separate materials such as liquids from solids or solids from solids. Typically such separators have a basket or other screen holding or mounting apparatus mounted in or over a receiving receptacle or tank and vibrating apparatus for vibrating the basket. One or more screens is mounted in the basket. Material to be treated is introduced to the screen(s) either by flowing it directly onto the screen(s) or by flowing it into a container, tank, or xe2x80x9cpossum bellyxe2x80x9d from which it then flows to the screen(s). Also in some multi-screen apparatuses material flows from an upper screen onto a lower screen.
Often there is wear in the area at which material is first introduced to a screen. Fluid alone and/or abrasive and solids in some fluids can wear away parts of a screen in the material introduction area. Such wear can cause so much damage to a screen that, although the remainder of the screen is serviceable, the screen must be repaired or replaced.
Referring now to FIG. 20, a prior art shale shaker 1 has a screen 2 (with screen or screening cloth or mesh as desired) mounted on vibratable screen mounting apparatus or xe2x80x9cbasketxe2x80x9d 3. The screen 2 may be any known screen or screens. The basket 3 is mounted on springs 4 (only two shown; two as shown are on the opposite side) which are supported from a frame 6. The basket 3 is vibrated by a motor 5 and interconnected vibrating apparatus 8 which is mounted on the basket 3 for vibrating the basket and the screens. Elevator apparatus 7 provides for raising and lowering of the basket end. Typically the basket will be in a xe2x80x9cclimb the hillxe2x80x9d position (e.g., see FIG. 23) so that a pool 9 of liquid is maintained at one end within the basket.
FIG. 21 discloses one example of a typical prior art shaker system (e.g. as shown in U.S. Pat. No. 5,190,645 incorporated fully herein for all purposes). The system A has a shale shaker K having a screen or screens S. The screen(s) S are mounted in a typical shaker basket B and one or more vibrators V (any known suitable shaker vibrator) vibrate the basket B and hence the screen(s) S. The other components of the system A are as described in U.S. Pat. No. 5,190,645.
FIG. 22 shows schematically a prior art system C with a Mud Box (Back tank, Possum Belly) to distribute the flow to a screening surface. The screens are mounted in a Deck (Basket) which is vibrated to assist the throughput of mud and movement of separated solids. The deck rests on Vibration Isolation Members, such as helical springs or rubber mounts. The vibration isolation members rest on the support member, which is also used to divert flow as desired, and is called a Bed. There are many deck, basket configurations used depending on the design criteria. The deck and basket, may be flat, horizontal, or mounted at a slope.
On sloped deck units (e.g. cascade or parallel flow), the screens may be continuous with one screen covering the entire deck length, or have a divided deck which has more than one screen used to cover the screening surface, or with individual screens mounted at different slopes. On multiple deck units, more than one screen layer may be employed. In a two or three deck unit, the material, fluid, drilling fluid, or mud passes through one screen before flowing through the second.
There is a need, recognized by the present inventors, for an efficient and effective screen support and screen for vibratory separator systems which does not wear excessively at the area of material introduction. There is a need, recognized by the present inventors, for an efficient and cost-effective screen support and screens with such a support that reduce wear in material introduction areas and which need not be repaired or replaced as frequently as certain prior art screens.
The present invention, in certain aspects, discloses a support for a screen assembly for a vibratory separator or a shale shaker, the support having a body, a first series of holes (or openings) through the body, each of the first series of holes having a first opening size as viewed from above, a second series of holes (or openings) through the body, each of the second series of holes having a second opening size as viewed from above, the second series of holes at a selected area of the body (e.g., a material introduction area or a material exit area) and the support positionable in a vibratory separator or shale shaker so that the selected area is adjacent a selected location with respect to the vibratory separator shale shaker (e.g., at an area of material introduction and/or material exit), and the second opening size smaller than the first opening size, and/or in certain aspects the holes or openings of the second series different in shape (as viewed from above) than the shape of the holes of the first series as viewed from above; and/or the holes or openings of the second series spaced-apart with a different spacing than spacing apart of the holes or openings of the first series. The present invention also discloses a screen assembly with such a support. The present invention also discloses a plastic grid for a screen assembly with such holes or openings.
The present invention discloses, in at least certain aspects, a support for a screen or screen assembly for a shale shaker or other vibratory separator. Such a support has at least two areas, including a first areas with a series of typical holes, perforations, or openings as in various prior art screens and screen assemblies; and at least one second area located at a material introduction area in which the holes, etc. are smaller than the holes, etc. in the first area and/or in which the holes, etc. are spaced further apart from each other than are the holes, etc. in the first area. Thus, in certain aspects of the present invention, there is more structure and/or mass in the second area than in the first area so that the second area does not wear as quickly as it would if its holes, etc. were like the holes, etc. of the first area. In one aspect the support is one integral piece with different holes and/or holes with different size and/or holes with different shapes and/or holes spaced differently; and, in other aspects, the support is a primary piece with one or more secondary pieces thereon whose effect is to produce a the different holes etc.
A shaker, in one embodiment according to the present invention, e.g. with basic components as the shaker in FIG. 20, is, according to the present invention, provided with one or more screens as described herein according to the present invention.
Screens according to certain aspects of the present invention may be made with plastic grids with holes, etc. that correspond to the holes, etc. of a support according to the present invention. In one aspect, the effective opening size of holes or openings at a fluid introduction area of a screen assembly is reduced by adding plastic, glue, epoxy and/or other adhesive around the holes in the fluid introduction area, thus strengthening this area. Also, such material can cross over and/or extend within and/or line the sides of a hole or opening in a support. In another aspect, the different holes, etc. are produced by a pattern of hot melt glue.
In certain aspects, supports according the to the present invention have more mass and/or more structural members at areas of fluid or material introduction to counter wear in those areas.
When a basket in a shaker has one elevated end (as shown in FIG. 23) so that the separated solids run xe2x80x9cuphillxe2x80x9d, liquid is prevented from running off the screen""s exit end; and a pool of liquid can be formed at the basket""s opposite end. Teachings of the present invention for material introduction areas can also be used at the screen areas beneath such a pool.
The present invention, in one embodiment includes a shale shaker with a frame; a xe2x80x9cbasketxe2x80x9d or screen mounting apparatus in the frame; one or more screens according to the present invention with supports according to the present invention in the basket; basket vibrating apparatus; and a collection tank or receptacle below the basket. In one particular aspect such a shale shaker treats drilling fluid.
The present invention discloses, in certain aspects, a method for reducing the wear on certain screen areas by using a screen or screens according to the present invention with screen supports according to the present invention.
It is, therefore, an object of at least certain preferred embodiments of the present invention to provide:
New, useful, unique, efficient, non-obvious screen supports for screens for vibratory separators and shale shakers and methods for using them to separate components of material to be treated thereby;
Such screen supports, and screens therewith, in which openings through a screen support are smaller and/or spaced closer together at a fluid introduction area than other openings through the screen support;
Such screen supports, and screens therewith, with one or more areas of increased mass and/or with relatively more structural members;
Such screen supports, and screens therewith, with an area or areas for initially receiving material to be treated, such areas with fewer holes, etc. than other areas of the screen support;
Such screen supports, and screens therewith, in which the effective opening size of openings at a fluid introduction are reduced compared to other openings of the support;
Such screen supports in which effective opening size at a fluid introduction area is reduced by superimposing an additional member with openings therethrough over part of a support at a fluid introduction area;
Such screens made with a plastic grid with holes, etc. corresponding to holes, etc. in a screen support according to the present invention;
Screens with one or more areas of tighter mesh at an area of expected excessive wear, e.g. at a material introduction and/or at an area of material exit; and
A system with any such screen support that has relatively increased screen life.
The present invention recognizes and addresses the previously-mentioned problems and long-felt needs and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one of skill in this art who has the benefits of this invention""s realizations, teachings, disclosures, and suggestions, other purposes and advantages will be appreciated from the following description of preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent""s object to claim this invention no matter how others may later disguise it by variations in form or additions of further improvements.